Carbon Rotofluid's 600S multi port rotary union consolidates multiple fluid circuits into a single precision assembly, with every circuit fully enclosed in its own sealed annular passage — isolated from every other circuit by dedicated carbon face seals and intermediate seal stages, with zero cross-contamination.
Industrial machines that heat, cool, or condition materials through rotating rolls, drums, and cylinders are increasingly built around multi-circuit fluid systems. A single roll may need to receive heated thermic oil in one passage, return it through a second, and carry an independent cooling water circuit through a third — all simultaneously, all through the same rotating journal. Fitting a separate conventional rotary union for each circuit is impractical: it multiplies the number of potential leak points, creates a cluttered shaft end that is difficult to maintain, and in many machine layouts is simply not physically possible. Carbon Rotofluid multi-port rotary unions consolidate multiple fluid circuits into a single precision assembly — a compact, maintainable connection point that handles the full fluid complexity of the machine without compromise on sealing integrity or service life.
The defining engineering challenge in a multi-port union is keeping circuits that share a common housing and rotate on the same shaft completely separate from one another.
Fitting a separate conventional rotary union for each circuit multiplies the number of potential leak points, creates a cluttered shaft end that is difficult to maintain, and in many machine layouts is simply not physically possible.
Each fluid circuit occupies a discrete annular channel within the union body, bounded on both sides by its own independently spring-loaded carbon face seal — lapped to a precision flatness that prevents inter-passage migration even at different operating pressures.
Carbon Rotofluid achieves absolute circuit separation through a concentric passage arrangement in which each fluid circuit occupies a discrete annular channel within the union body.
Each channel is bounded on both sides by its own independently spring-loaded carbon face seal, lapped to a precision flatness that prevents inter-passage migration even when adjacent circuits operate at different pressures.
Between the seal stages, a vented intermediate cavity acts as a visual leakage indicator — if either bounding seal begins to wear, media migrates to the cavity and exits through the vent port before it can reach the adjacent circuit.
The stainless steel rotor carries internal drillings that connect each annular channel at the seal interface to its individual port connection at the rotating end — a dedicated, isolated path per circuit, with no shared internal volume where media could mix.
This arrangement gives maintenance teams early warning of seal wear on any single passage, without any risk of cross-contamination reaching the process media in adjacent circuits.
Multi-port unions are not limited to circuits carrying the same medium. Each circuit is specified independently for operating pressure, temperature, flow rate, and media compatibility — with seal grades, O-ring materials, and housing alloys selected for the most demanding circuit and reviewed for compatibility across all circuits before manufacture.
Steam and condensate return carried in adjacent passages, eliminating the need for separate unions at both ends of a steam-heated roll.
Thermic fluid supply and return with an independent cooling water circuit for emergency quench or controlled cooling during shutdown sequences.
Hydraulic actuation fluid and process cooling water on spindles where both functions must operate simultaneously.
Two temperature zones of thermic fluid at different set-point temperatures on the same wide-format roll, fed from independent temperature control circuits.
Multi-port unions are manufactured to order across a wide bore range, from small-diameter spindle unions with two compact passages to large-bore assemblies with four or more circuits for complex multi-zone rolls.
From small-diameter spindle unions with two compact passages to large-bore assemblies with four or more circuits for complex multi-zone rolls.
Port connections are available in BSP, NPT, or metric thread forms on the stationary body, with flanged connections available for larger sizes or where the pipework layout requires it.
The stationary body can be configured for radial port entry, axial port entry, or a combination, depending on the pipework routing at the machine end. Anti-rotation support arrangements are designed into the union body to suit the machine's structural geometry.
Because each multi-port union is assembled to a specific circuit configuration, dimensional drawings are provided for approval before production begins, and each assembly is pressure-tested before despatch.
| Passage architecture | Concentric annular channels, single shaft |
| Circuit isolation | Dedicated carbon face seal per channel |
| Leak indication | Vented intermediate cavity between seal stages |
| Rotor | Stainless steel, dedicated internal drillings per circuit |
| Media | Steam, condensate, thermic fluid, cooling water, hydraulic fluid |
| Circuit count | Two passages (spindle) to four or more (multi-zone rolls) |
| Port connections | BSP, NPT, or metric; flanged options for larger sizes |
| Port entry | Radial, axial, or combined, per pipework layout |
The specification process covers the number of circuits, the medium and operating parameters for each, the bore and journal dimensions, the required port connections, and any space constraints at the machine end.
The number of independent circuits required and the medium and operating parameters — pressure, temperature, flow rate — for each one.
The bore range and journal dimensions of the union, matched to the machine's shaft end and available space.
The required port connections — BSP, NPT, metric, or flanged — and any space constraints at the machine end that affect radial or axial port entry.
Carbon Rotofluid's engineering team produces a dimensional drawing for approval before production begins, and pressure-tests the completed assembly to confirm seal integrity across all circuits before despatch. Contact the Carbon Rotofluid technical team to begin a specification for your application.